JP6571958B2 - Ultrasonic inspection equipment - Google Patents

Description

  The present invention relates to an ultrasonic inspection apparatus, and more particularly to an ultrasonic inspection apparatus that visualizes an object to be measured present in a medium.

  2. Description of the Related Art Conventionally, an ultrasonic transmission unit that emits ultrasonic waves and an optical fiber that irradiates and enters laser light, and a reflected wave (received signal) of an ultrasonic wave emitted from the ultrasonic transmission unit by a measurement object 2. Description of the Related Art An ultrasonic inspection apparatus that receives an image through an optical fiber and analyzes a received signal to image a measurement object is known (for example, see Patent Documents 1 and 2 below).

Japanese Patent No. 3021176 Japanese Patent No. 4898247

  However, in the above-described conventional technique, for example, as shown in FIG. 6, the portions 65 and 66 of the reflected wave 62 from the object to be measured propagate through the inside of the sensor body 01 and the receiving surface 02 and are received. When the point P is reached, there is a problem that noise of the original received signal (actual signal) is generated, and this causes deterioration of the image when the object to be measured is imaged. In addition, when a plurality of reception sensors are provided for one transmission sensor and imaging is performed by aperture synthesis processing, it is necessary to provide a large number of reception sensors in order to improve reception sensitivity. In short, there is a problem that the cost of the apparatus is increased.

  In view of the above, an object of the present invention is to provide an ultrasonic inspection apparatus capable of reducing noise superimposed on a received signal and improving visibility in imaging.

An ultrasonic inspection apparatus according to a first invention for solving the above-described problem is
A transmission sensor that transmits ultrasonic waves to an object to be measured existing in the medium;
A support having a through hole, and a receiving sensor having a metal film covering the surface of the through hole and the support,
Wherein an ultrasonic inspection apparatus which performs visualization of pre Symbol object to be measured by analyzing the vibration of the metal film member according to the reflected wave of the ultrasonic wave reflected by the object to be measured,
A propagation preventing plate that has heat resistance and reflects ultrasonic waves is provided between the support and the metal film body.

The ultrasonic inspection apparatus according to the second invention is the ultrasonic inspection apparatus according to the first invention.
The propagation preventing plate is made of a material having an acoustic impedance different from that of the support body and the metal film body.

Moreover, the ultrasonic inspection apparatus according to the third invention is the ultrasonic inspection apparatus according to the second invention.
The propagation preventing plate is made of fluororubber.

  According to the ultrasonic inspection apparatus according to the present invention described above, noise superimposed on the received signal can be reduced, and the signal strength of the received signal can be relatively improved. Thereby, the distance to the measurement object can be measured with high accuracy, and the visibility when the measurement object is visualized by image processing can be improved. In addition, when a plurality of reception sensors are provided for one transmission sensor and the object to be measured is visualized by aperture synthesis processing, the same visibility as a conventional ultrasonic inspection device is ensured even if the number of effective reception points is reduced. Therefore, the manufacturing cost can be reduced by reducing the number of reception sensors.

1 is a schematic configuration diagram of an ultrasonic inspection apparatus according to an embodiment of the present invention. It is sectional drawing which shows the sensor part of the ultrasonic inspection apparatus which concerns on the Example of this invention. It is explanatory drawing which shows the structure of the receiving sensor of the ultrasonic inspection apparatus which concerns on the Example of this invention. FIG. 3 is an enlarged view of a main part of FIG. 2. It is a graph which shows an example of the reception ultrasonic waveform acquired on the same conditions, FIG.5 (a) is a reception ultrasonic waveform by the ultrasonic inspection apparatus which concerns on the Example of this invention, FIG.5 (b) is conventional. The received ultrasonic waveform by an ultrasonic inspection apparatus is shown. It is explanatory drawing which shows the example of the reflected wave which propagates the inside of the conventional sensor main body, and a receiving surface.

  Hereinafter, the details of the ultrasonic inspection apparatus according to the present invention will be described with reference to the drawings.

An ultrasonic inspection apparatus according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the ultrasonic inspection apparatus according to the present embodiment includes a sensor unit 10 having a transmission sensor 11 and a reception sensor 12, an optical processing unit 20 that converts an optical signal into an electrical signal, and an optical processing unit 20. And a visualization unit (for example, a monitor or the like) 30 that performs aperture synthesis processing (image processing) based on an electrical signal input from the image and images the object to be measured 50 (see FIG. 2).
Note that the configurations of the optical processing unit 20 and the visualization unit 30 are the same as those already known, and a detailed description thereof is omitted here.

As shown in FIGS. 1 and 2, in this embodiment, a plurality of (for example, nine) transmission sensors 11 are provided in a cylindrical housing 13 and are formed on a backup plate 14 described later. The through holes are two-dimensionally and intermittently arranged and fixed so as to be spaced apart from each other at regular intervals. The transmission sensor 11 is made of, for example, a piezoelectric element, and emits ultrasonic waves to the object to be measured 50.
In addition, the code | symbol 40 in FIG. 2 is a medium (for example, liquid sodium etc.).

  The reception sensor 12 has a large number (for example, about 2500) of through-holes (hereinafter referred to as reception sensor through-holes) 14c and covers the opening of the housing 13; A diaphragm (metal film body) 16 covering the surface and the through-hole 14c is provided. The backup plate 14 is made of a solid metal material (for example, nickel, hereinafter referred to as a solid material), and the reception sensor through holes 14c are two-dimensionally spaced apart from each other at regular intervals around each transmission sensor 11. Each is arranged in multiple numbers. The diaphragm 16 is made of, for example, a metal foil made of nickel. As shown by a broken line in FIG. 3, the portion of the diaphragm 16 that covers the reception sensor through-hole 14 c is super-radiated from the transmission sensor 11. The sound wave 61 is configured to vibrate by a reflected wave 62 reflected by the measurement object 50. In addition, the part facing the transmission sensor 11 of the said diaphragm 16 is opening, and, thereby, the transmission surface of the transmission sensor 11 is in the exposed state.

  As shown in FIGS. 3 and 4, the optical fiber 15 is fixed to the receiving sensor through hole 14 c of the backup plate 14 in a non-contact manner with the diaphragm 16, and the tip of the optical fiber 15 is the diaphragm 16. It is in the state covered by non-contact by. More specifically, as shown in FIG. 4, the optical fiber 15 has a backup plate via a ferrule 17 such that the tip of the optical fiber 15 is positioned on the inner side (opposite side of the diaphragm 16) of the backup plate 14 on the diaphragm 16 side. 14 is fixed. Then, as shown in FIG. 3, a laser beam (hereinafter referred to as inspection laser light) 63 is irradiated to the diaphragm 16 through the optical fiber 15, and the reflected laser beam reflected by the diaphragm 16 of the inspection laser light 63. Light 64 enters the optical fiber 15. That is, in this embodiment, the vibration of the diaphragm 16 is regarded as the modulation of the reflected laser beam 64 with respect to the inspection laser beam 63, and this is received as a received signal (pulse).

  Further, in the ultrasonic inspection apparatus according to the present embodiment, a propagation preventing plate 18 is provided between the backup plate 14 and the diaphragm 16. The propagation preventing plate 18 is a material that has heat resistance and reflects ultrasonic waves. More specifically, the propagation preventing plate 18 has an acoustic impedance different from that of the diaphragm 16, and most of the ultrasonic waves propagated through the diaphragm 16 are separated from the diaphragm 16. It consists of material (for example, fluororubber) which has the acoustic impedance of the magnitude | size which can be reflected in the interface with the said propagation prevention board 18 concerned.

  3 and 4, the distance between the optical fiber 15 and the diaphragm 16 is exaggerated for easy understanding of the relationship between the optical fiber 15 and the diaphragm 16. Further, the thickness of the propagation preventing plate 18 shown in FIGS. 3 and 4 is an example, and it is needless to say that the thickness can be appropriately changed as necessary.

Hereinafter, the effect of the ultrasonic inspection apparatus according to the present embodiment will be described with reference to FIGS. 3 and 4.
As shown in FIG. 3, the ultrasonic wave 61 emitted from the transmission sensor 11 (see FIGS. 1 and 2) is reflected by the object to be measured 50 and is reflected as a reflected wave 62 on the sensor unit 10 (see FIGS. 1 and 2). Come back. On the other hand, the inspection laser light 63 emitted from the optical fiber 15 is reflected by the diaphragm 16 as described above because the tip of the optical fiber 15 is covered by the diaphragm 16, and is reflected as reflected laser light (received signal) 64. The light enters the optical fiber 15.

  Here, when the reflected wave 62 emitted from the transmission sensor 11 and reflected by the measurement object 50 reaches the diaphragm 16, the diaphragm 16 vibrates as indicated by a broken line in FIG. 3, thereby being reflected by the diaphragm 16. The reflected laser beam 64 is modulated as compared with the inspection laser beam 63.

  In this embodiment, light modulation between the inspection laser light 63 and the reflected laser light 64 obtained by each receiving sensor 12 is converted into an electrical signal by the optical processing unit 20, and aperture synthesis processing is performed by the visualization unit 30. By doing so, the shape of the measurement object 50 is imaged.

  At this time, in the ultrasonic inspection apparatus according to the present embodiment, the propagation preventing plate 18 that reflects ultrasonic waves is provided between the backup plate 14 and the diaphragm 16, so that the diaphragm 16 is reflected by the measurement object 50. Most of the reflected wave 62 that has propagated is reflected by the propagation preventing plate 18 due to the difference in acoustic impedance (see the arrow in FIG. 4).

  FIG. 5 shows a result of comparison between a received ultrasonic waveform obtained by the ultrasonic inspection apparatus according to the present embodiment and a received ultrasonic waveform obtained by a conventional ultrasonic inspection apparatus. As shown in FIG. 5A, according to the ultrasonic inspection apparatus according to the present embodiment, the propagation preventing plate 18 is provided between the backup plate 14 and the diaphragm 16, so that the reflected wave 62 is prevented from propagating. Since it is reflected by the plate 18 and the generation of noise due to a part of the reflected wave 62 propagating through the backup plate 14 and reaching the reception point as in the prior art is suppressed, the noise is superimposed on the received signal. In general, only the received signal at the ultrasonic receiving surface could be measured. On the other hand, as shown in FIG. 5B, it can be seen that in the conventional structure, a wave passing through the structure such as the backup plate 14 is included as noise in addition to the received signal on the ultrasonic wave receiving surface.

  As described above, according to the ultrasonic inspection apparatus according to the present embodiment, the reflected wave 62 reflected by the measurement target object 50 is reflected by the propagation preventing plate 18 and the reflected wave 62 enters the backup plate 14. The noise is not superimposed on the received signal (pulse) by being further reflected inside the backup plate 14 and reaching the diaphragm 16, and the signal strength of the received signal can be relatively improved. The visibility of the visualized image can be improved. Further, even if the number of effective reception points is reduced, it is possible to ensure the same visibility as that of the conventional ultrasonic inspection apparatus for the visualized image, so that the manufacturing cost can be reduced by reducing the number of reception sensors.

  In the above-described embodiment, an example in which the transmission sensor 11 and the reception sensor 12 are integrally provided is shown as the configuration of the sensor unit 10, but the transmission sensor 11 and the reception sensor 12 are provided integrally. It is not necessary and can be applied to any apparatus provided with a transmission sensor that emits an ultrasonic wave and a reception sensor that receives a reflected wave reflected by an object to be measured, and does not depart from the spirit of the present invention. It goes without saying that various changes can be made within the range. The same applies to the embodiments described below.

  Further, in the above-described embodiment, the example in which the plurality of transmission sensors 11 are two-dimensionally arranged and the reception sensor through holes 14c are two-dimensionally arranged around the transmission sensor 11 has been described. The number of sensors 11 may be one, and the arrangement of the transmission sensor 11 and the reception sensor through hole 14c may be one-dimensional, and may be arranged as necessary.

In the above-described embodiment, an example in which laser light transmitted through the optical fiber 15 is used as a means for detecting the vibration of the diaphragm 16 is shown. As a means for detecting the vibration of the diaphragm 16, for example, Other means such as a vibrator can be used.
Further, in the above-described embodiment, the fluororubber is used as the material of the propagation preventing plate 18, but the acoustic impedance is large enough to have heat resistance and to reflect the ultrasonic wave at the boundary between the backup plate 14 and the diaphragm 16. Other materials may be used as long as they have materials.

  The present invention is suitable for application to an ultrasonic inspection apparatus that measures and visualizes an object to be measured existing in a medium from a position away from the object to be measured.

DESCRIPTION OF SYMBOLS 01 Sensor main body 02 Reception surface 10 Sensor part 11 Transmission sensor 12 Reception sensor 13 Housing 14 Backup plate 15 Optical fiber 16 Diaphragm 17 Ferrule 18 Propagation prevention plate 20 Optical processing part 30 Visualization part 40 Medium 50 Measurement object 61 Ultrasonic wave 62 Reflection Wave 63 Inspection laser beam 64 Reflected laser beam 65 Part of reflected wave 66 Part of reflected wave

Claims (3)

A transmission sensor that transmits ultrasonic waves to an object to be measured existing in the medium;
A support having a through hole, and a receiving sensor having a metal film covering the surface of the through hole and the support,
Wherein an ultrasonic inspection apparatus which performs visualization of pre Symbol object to be measured by analyzing the vibration of the metal film member according to the reflected wave of the ultrasonic wave reflected by the object to be measured,
An ultrasonic inspection apparatus, wherein a propagation preventing plate having heat resistance and reflecting ultrasonic waves is provided between the support and the metal film body. The ultrasonic inspection apparatus according to claim 1, wherein the propagation preventing plate is made of a material having an acoustic impedance different from that of the support body and the metal film body. The ultrasonic inspection apparatus according to claim 2, wherein the propagation preventing plate is made of fluororubber.

Images